Kuyini viscosity? viscosity nesilinganiso iyunithi

Viscosity uchaza ikhono zoketshezi noma amagesi ukudala ukumelana phakathi ezihambayo isihlobo komunye nomunye izingqimba uketshezi (hhayi eliqinile) emizimbeni. Okusho ukuthi, leli nani sifana amandla friction yangaphakathi (elithi ngesiNgisi: viscosity), lisuselwa ukunyakaza igesi noma uketshezi. Ngokuba izidumbu ezahlukene iyohluka, njengoba kuncike yimvelo yabo. Ngokwesibonelo, amanzi has a viscosity ongaphakeme kuqhathaniswa uju, okuyinto viscosity elingaphezulu kakhulu kwaleli. Ukungqubuzana yangaphakathi noma fluidity okuqinile (ngobuningi) impahla libhekene izici rheological.

Igama viscosity livela Latin Viscum, okusho ukuthi Mistletoe. Lokhu kungenxa le nyoni-lime, okuyinto Yenziwe Mistletoe amajikijolo kanye esetshenziselwa ekubambeni izinyoni. Yesigcilikisha ezigcotshwe amagatsha esihlahla nezinyoni wahlala phezu kwazo, baba izisulu ezilula abantu.

Kuyini viscosity? Amayunithi yokukala izici uzonikezwa, njengoba kuyisiko, ohlelweni SI, kanye nabanye abangewona SI amayunithi.

U-Isaac Newton 1687, ukusungula umthetho eziyisisekelo ukugeleza emizimbeni liquid gaseous: F = ƞ • {(v2 - v1) / (Z2 - Z1)} • S. Kulokhu, F - ungamandla (tangential) elibangela shift of izingqimba ezithathekayo umzimba. Isilinganiso (v2 - v1) / (Z2 - Z1) ikhombisa izinga soshintsho liquid noma igesi ukugeleza velocity e ushintsho komunye ungqimba kwenye ngezinhlamvu ezihlelwa ngesandla. Kungenjalo eyaziwa ngokuthi ukugeleza Isivinini umyela noma izinga phuca. Ubukhulu S - iyona ndawo (esigabeni cross) ezithathekayo umzimba ukugeleza. Ƞ Isici proportionality kuyinto Coefficient viscosity of ashukumisayo walo mzimba. Usayizi, ephambene yayo j = 1 / ƞ, a fluidity. Force wayenethonya per unit endaweni (esigabeni cross) ukugeleza kungenziwa ibalwe ifomula: μ = F / S. Kuyinto ngokuphelele noma viscosity ashukumisayo. Amayunithi yokukala ohlelweni SI, ke ungaboniswa lesibili pascal.

Viscosity kuyinto ebaluleke ngokomzimba-chemical izici izinto eziningi. Inani layo ku-akhawunti e-design kanye nokusebenza piping kanye namadivayisi lapho kukhona ukunyakaza (isib, uma asetshenziselwa ukudonsa) medium liquid noma gaseous. Kungaba uwoyela, igesi futhi-imikhiqizo yabo, slag oncibilikisiwe noma ingilazi, nokunye. Viscosity ezimweni eziningi kuba isici qualitative of ushintsho kanye nemikhiqizo sokugcina ahlukahlukene silwenza, ngoba incike isakhiwo we ketshezi futhi ubonisa isimo physico-amakhemikhali impahla kanye nezinguquko kwezobuchwepheshe. Ngokuvamile, ukulinganisa ukumelana ukusonteka is Ungasebenzisi noma kuphela isikhathi sokuthatha viscosity ashukumisayo futhi kinematic, okuyinto amayunithi SI Amayunithi obonakaliswe square metres ngomzuzwana. viscosity Kinematic (okhonjiswe ν) kuyinto isilinganiso viscosity ashukumisayo (μ) ukuze kwabantu uketshezi (ρ): v = μ / ρ.

viscosity Kinematic - a izici physico-chemical indaba, okubonisa ikhono lawo ngaphansi isenzo amandla adonsela phansi simelane ukugeleza.

I SI iyunithi kinematic viscosity nesilinganiso kubikwa njengoba m2 / s.

Esikhathini CGS uhlelo viscosity kukalwa ngesikhathi Stokes (St) noma centistokes (cSt).

Phakathi kwalezi zimo amayunithi wokulinganisa kukhona ubuhlobo ezilandelayo: Cm 1 = 10-4 m2 / s, bese 1 cSt = 10-2 Cm = 10-6 m2 / s = 1 mm2 / s. Ngokuvamile viscosity kinematic kukhona omunye iyunithi non-letindzala yokukala - lokhu osengowakwa-Engler degrees, okuyinto ukudlulisa Stokes kungenziwa eyenziwa ifomula enokwehla: v = 0,073oE - 0.063 / œ noma itafula.

Ukuguqula viscosity okuguquguqukayo ohlelweni amayunithi ingasetshenziswa kwesibalo extrasystematic: 1 Pa • c = 10 poises. Shorthand kulotshiwe ukuthi: AP

Ngokuvamile amayunithi ihanjiswa uketshezi viscosity imibhalo normative ku kokuqendwa (commercial) umkhiqizo noma inqubo izidingo ku interm kanye nohlu elamukelekayo Enye izici qualitative nangamalungu nephutha angakahleleki.

Ukuze sithole viscosity ngaphansi laboratory noma izimo zezimboni kukhona viscometers imiklamo ehlukahlukene. Zingaba rotary, nge ibhola, capillary, ultrasonic. Isimiso sokukala viscosity a viscometer ingilazi capillary esekelwe ekunqumeni isikhathi kokuphela ketshezi ngokusebenzisa ulinganiswe capillary tube ka ububanzi ezithile futhi ubude, njalo viscometer okumelwe icatshangelwe. Njengoba viscosity of indaba incike lokushisa (nge okwandisa yiso uzokwehla ngenxa yamangqamuzana theory kinetic ngenxa ukusheshisa motion okungahleliwe kanye nokuxhumana zishintshe), ukuze test isampula kufanele kugcinwe isikhashana ezingeni lokushisa ethile ngoba alinganiselwa wokugcina kulo umthamo isampula. Kukhona izindlela eziningana zifane viscosity ukuhlolwa, kodwa ezivamile - kuyinto kwemibuso ejwayelekile GOST 33-2000, okuyinto kunqunywa esekelwe viscosity kinematic, amayunithi kulokhu mm2 / s (cSt), kanye viscosity ashukumisayo is recalculated njengoba umkhiqizo viscosity kinematic ngu kwabantu.